September 16, 2014

MySQL caching methods and tips

“The least expensive query is the query you never run.” Data access is expensive for your application. It often requires CPU, network and disk access, all of which can take a lot of time. Using less computing resources, particularly in the cloud, results in decreased overall operational costs, so caches provide real value by avoiding […]

Ultimate MySQL variable and status reference list

I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and […]

High-Performance Click Analysis with MySQL

We have a lot of customers who do click analysis, site analytics, search engine marketing, online advertising, user behavior analysis, and many similar types of work.  The first thing these have in common is that they’re generally some kind of loggable event. The next characteristic of a lot of these systems (real or planned) is […]

Multiple column index vs multiple indexes

(There is an updated version of the content in this post by Percona’s Stephane Combaudon available here.) After my previous post there were questions raised about Index Merge on Multiple Indexes vs Two Column Index efficiency. I mentioned in most cases when query can use both of the ways using multiple column index would be […]

MySQL Full Text Search in Action

Preparing to move I’m selling stuff on GumTree which is UK based clone of Craigslist offering similar functionality but with Ads Similarly to Craigslist GumTree is powered by MySQL but unlike craigslist it looks like they are shy in tuning their MySQL Full Text Search index configuration and setting proper ft_min_word_len value. Searching for Audi […]

Read Buffers, mmap, malloc and MySQL Performance

Monty Taylor posted interesting investigation of the fact read_buffer_size variable affects connection speed. This is not something you would expect right ? me too. Not only global user data is expected to be cached on startup but even if it is not why would you do full table scan to fetch single user information ? […]

Innodb Recovery Update – The tricks what failed.

As I wrote we had been recovering corrupted Innodb Tablespace and it is finally done now. As this was over than 1TB worth of data we really tried to avoid dumping the data and find some other way to recovery. Examining Innodb page content and crash information we figured out it should be page of […]

Duplicate indexes and redundant indexes

About every second application I look at has some tables which have redundant or duplicate indexes so its the time to speak about these a bit. So what is duplicate index ? This is when table has multiple indexes defined on the same columns. Sometimes it is indexes with different names, sometimes it is different […]

OpenStack users shed light on Percona XtraDB Cluster deadlock issues

I was fortunate to attend an Ops discussion about databases at the OpenStack Summit Atlanta this past May as one of the panelists. The discussion was about deadlock issues OpenStack operators see with Percona XtraDB Cluster (of course this is applicable to any Galera-based solution). I asked to describe what they are seeing, and as […]

Percona XtraDB Cluster 5.5.34-25.9 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.34-25.9 on December 4, 2013. Binaries are available from the downloads area or from our software repositories. Based on Percona Server 5.5.34-32.0 including all the bug fixes in it, Galera Replicator and on Codership wsrep API 5.5.34-25.9, Percona XtraDB Cluster 5.5.34-25.9 is now the […]